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Blu3wolf -> RE: Amazed at defensive prowess of modern fighters. (2/1/2014 3:00:43 PM)
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quote:
ORIGINAL: jdkbph
You know... as someone else said, this is a war game, not a flight simulator. I'm guessing we're not directly modeling the physics associated with each and every aircraft and missile in the air during the course of a scenario.
If that's true, why not just go with a quick, simple (but hopefully effective) fix first then refine (if necessary) as time goes on?
For instance, take a base number... lets say 20 seconds (I'll let the experts argue over what's appropriate here)... as the recovery period for a "standard" fighter class aircraft flown by a "standard" quality pilot, after having successfully evaded a missile. These two values (standard fighter and standard pilot) could be further modified by aircraft generation (or if you want to get even more detailed, by factors such as T/W ratio) and side quality respectively.
During this recovery period, the PK for subsequent missile attacks would simple be increased by some amount. Stack these modifiers and you'd simulate, in a reasonable and simple way (I think), the situation where a plane goes from a high energy state to a low energy state due to evasive maneuvering.
JD
such a simple set up is likely what will happen, but the issue is picking somewhat realistic values for such penalties, and making sure that such a penalty is in fact realistic.
quote:
ORIGINAL: mikmyk
Does the E-M diagram tell you how long the penalty should last or cover every possible case?
Those are the issues we have to tackle.
Might not be hard but you have to be thoughtful[:)]
Thanks!
okay. The E-M (Energy to Maneuverability) diagram plots airframe energy against its performance, typically expressed as altitude of potential energy lost against degrees per second turn rate.
what it tells you is how much energy it costs to maneuver the aircraft. If you read on the (for example) 9G line on the graph at the 22.6 degrees per second line to find that it loses 1600 ft per second, you can see how well the aircraft can maneuver, for how much energy cost (for a given airspeed/altitude).
If you want to apply a penalty to the aircraft for losing energy, then first you need to determine how much energy the aircraft must expend to defeat a missile kinematically. If the aircraft is trying to outturn the missile (common conception, also the least effective avoidance maneuver), then it will lose lots of energy, for a small chance to defeat the missile; it would also have a penalty to its overall energy state for any subsequent missile shots, that would last until it could gain that much energy back, by converting fuel into speed and/or altitude. If you know how fast it can convert fuel into energy, and how much energy it expends for a 'standard' missile defence, then you can easily apply a penalty for a fairly accurate length of time. The magnitude of the penalty is equal to how much energy was expended; the duration of the penalty is until the aircraft gets back to its previous energy state (combination of airspeed and altitude).
Finding out how fast it can convert fuel into energy is something that standard acceleration charts would help with. For USAF aircraft I believe all these charts are published in the aircraft's -1-1 manual.
Realistically speaking, if you fly past the Range Turn and Run (Rtr) for the missile/adversary combination, then trying to break into a missile burns lots of energy and is only really effective against first generation SAMs.
Theres an old USAF paper kicking around on it somewhere, Ill have a look for it. The gist of the paper was that defeating the missile seeker was generally more reliable than trying to outmaneuver a missile, and produced much larger miss distances. They threw a series of missile attack scenarios into a computer simulation with the 'pilot' doing different maneuvers, notably beaming the missile and then breaking into it in the endgame, flying head on and breaking away from it in the endgame, flying head on without maneuvering (baseline for the test), and beaming the missile without a break turn. There was also a discussion on 'gaming' the missile using knowledge of its proportional navigation algorithms to make a series of small turns which made the missile constantly overcorrect its flight path; this relied on making precisely timed turns - perfectly accomplishable, provided you know the specs for the missile. Not considered practicable.
I recall that the small turns made the largest miss distances, followed by the beaming maneuvers. flying head on and breaking away works if the missile has very high closing distances and some small lag on fuzing. trying to break into the missile was not considered helpful by the paper.
I hope the discussion on energy states helps somewhat. Ill try find that paper as well, though its been a while since I read it and I dont recall whether I saved it to my HDD or not.
EDIT: I have appended an example E-M diagram, probably one of the most commonly seen ones floating around the net in fact. You may also be familiar with this graph referred to as a 'doghouse chart'... as it looks somewhat like a lopsided doghouse.
[image]http://images.blu3wolf.com/uploads/doghouse.PNG[/image]
EDIT II: I found the doc in question and it seems I have not reviewed it recently enough. The paper is fairly technical, but it is very clear in that its best maneuver to generate maximum miss distances was a series of short, max G jinks in directions 180 degrees apart. This would definitely mean an energy penalty of some kind to the aircraft over time.
Apologies for the misconception. Feel free to have a read though, its interesting stuff.
http://www.blu3wolf.com/falconbms/docs/MissileDefense.pdf
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